JPH11187696A - Control method and device for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the back motion speed of a scanner and improve SPM (sheets per minute). SOLUTION: A scanner is driven by a stepping motor and starts from a point (g) and returns to the point (g) through an acceleration period (a), a constant speed vibration absorbing period (b), a constant speed image reading period (c), a deceleration period (d), and a back period (e). An acceleration torque is increased in the periods (d) and (e), and an acceleration and a motor electric energy in the deceleration period and a motor electric energy in the back period are made so as to be made equal to each other to have the deceleration of the period (d) and the acceleration of the period (e) equal to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control method and apparatus suitable for an image reading apparatus in which a scanner is moved by using a stepping motor.

[0002]

2. Description of the Related Art A color image reading apparatus reads a document image by a scanning operation. A stepping motor is used as a power source for driving a carriage housing a scanning unit including a light source for scanning an image, an optical mirror, and the like, because of the necessity of speed control and positioning. Further, in an environment surrounding a color image reading apparatus, further improvement of sheet per minute (hereinafter referred to as SPM) which indicates the number of sheets that can read a document per unit time is required by improving the processing speed of a connected printer or computer. ing. In order to improve the SPM, an acceleration time for accelerating the motor to bring the scanning unit from the scan start position to the image reading scanning speed, a deceleration time for decelerating the motor to stop, and a scan start position from the motor stop position. It is necessary to reduce the motor control time other than the portion required for image reading, such as the returning back time.

[0003]

Conventionally, however, a motor uses a motor torque 1 used for acceleration / constant speed / deceleration operations for reading an image and a back operation for returning a motor stop position to a scan start position. Since the torque distribution of the scan sequence is performed as in the case of the motor torque 2 to be performed, there is a limit in increasing the speed of the scan.

Further, in order to reduce the acceleration time and deceleration time of the stepping motor, it is necessary to increase the power to be applied in order to increase the acceleration torque and increase the acceleration. And the power for constant-speed operation at zero acceleration during image reading was the same. If the power applied to the motor is increased to reduce the acceleration time, unnecessary acceleration torque is increased at the time of constant-speed operation when reading an image, and the vibration of the motor becomes large, causing a problem that the read color image is blurred. Was.

Next, FIG. 2 shows the cause of the motor vibration.
This will be described with reference to FIG. FIG. 2 shows the relationship between the acceleration torque for driving the load by the motor and the constant speed torque (load torque). In the figure, the x axis represents the motor drive frequency (pps), and the y axis represents the motor output torque (T). Tout is a motor output torque (pullout torque), Ta is a safe area for safely operating the motor, Tk2 is an acceleration torque area, and Tt2 is a load torque required for driving a load connected to the motor.

For example, in order to reduce the time for accelerating to the drive frequency P1, the area of the acceleration torque region Tk2 must be increased. Torque is increased by increasing the power applied to the motor. Therefore, the acceleration torque Tk2 at the drive frequency P1 also increases. After the acceleration of the motor is completed, the load torque required to drive the load at a constant speed at the drive frequency P1 is Tt2. Therefore, unnecessary acceleration torque Tk2 becomes excessive,
This causes motor vibration, and the constant-speed driving unit generates motor vibration according to the magnitude of the acceleration torque Tk2. When the motor vibration occurs, the document reading device vibrates, and there is a problem that the read image is blurred, and in the case of a color image, the color is shifted.

In order to return at high speed from the forward direction to the backward direction when reciprocating while controlling the position of the carriage or the like using the stepping motor, the carriage must be stopped as soon as possible in the forward direction and operated in the backward direction. There is a need. However, if the reciprocating motion is to be performed for a shorter time than the time required by the relationship between the load applied to the motor and the torque, there is a problem that the motor loses synchronism due to insufficient torque.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the SPM by reducing the motor control time other than the portion necessary for image reading without synchronizing the motor, and to prevent the motor from vibrating.

[0009]

According to the motor control method of the present invention, the rotation of the motor is transmitted to the moving object via the driving mechanism, thereby causing the moving object to reciprocate along a predetermined path. Therefore, in the motor control method of sequentially performing each control of acceleration, constant speed, deceleration, and reverse rotation of the motor, the amount of power supplied to the motor is the same during the deceleration control and the reverse rotation control. To control.

In the motor control method according to the second aspect of the present invention, the rotation of the motor is transmitted to the moving object via a driving mechanism, so that the moving object moves along a predetermined path. In the motor control method of sequentially performing each control of the constant speed and the deceleration, the power supplied to the motor at a predetermined timing after the transition from the acceleration to the constant speed is reduced.

In the motor control device according to the fifth aspect of the present invention, the rotation of the motor is transmitted to the moving object via the driving mechanism, so that the moving object reciprocates along a predetermined path. In a motor control device that sequentially performs each control of acceleration, constant speed, deceleration, and reverse rotation, the above control is performed, and the amount of power supplied to the motor becomes the same during the deceleration control and the reverse rotation control. Is provided.

In the motor control device according to the present invention, the rotation of the motor is transmitted to the moving object via the driving mechanism, so that the moving object moves along a predetermined path. A control device for controlling the motor, which sequentially performs each control of a constant speed and a deceleration, wherein the control unit performs each of the above controls and reduces the power supplied to the motor at a predetermined timing after shifting from the acceleration to the constant speed. Is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first to fifth embodiments of the present invention will be described with reference to the drawings. First, a first embodiment will be described. In the present embodiment, the torque used by the motor for acceleration / constant speed operation for reading an image is defined as motor torque 1, and the deceleration operation performed after the end of the image reading constant speed drive and the motor stop position to the scan start position. By changing the torque distribution of the scan sequence so that the torque used for the returning back operation is set to the motor torque 2, a series of scan operation times is shortened and the SPM is improved.

FIG. 1 is an image reading operation sequence diagram of the color image reading apparatus. In the figure, the x-axis direction is time,
The y-axis direction represents acceleration. The color image reading apparatus performs one sequence of image reading four times using a stepping motor as a driving source for reading images of C (cyan), M (magenta), Y (yellow), and Bk (black). In one operation for reading the document image 30, a series of operations of a rising portion a, a vibration absorbing portion b, an image reading portion c, a falling portion d, and a back portion e are performed from the operation start position g, and the operation starts. Return to position g.
The vibration absorbing portion b is provided to absorb the vibration of the reading system generated at the rising portion a and the vibration generated by switching between the current and the voltage.

In this embodiment, the acceleration torque Tk shown in FIG. 2 is increased in the section d and the section e in FIG. 1 to increase the motor acceleration in the section d and the section e. The time required for the series of motor operation sequences in FIG. 1 is reduced. At that time, the amount of power applied to the motor in the deceleration control and the back control is set to be the same so that the series of scan operation times is reduced so that the deceleration in the section d is equal to the acceleration used in the section e. I have to. For this purpose, in the section between f and g in FIG. 1, the voltage / current is increased to increase the acceleration torque Tk.

FIG. 3 is a schematic sectional view when the color image reading apparatus is used in a color copying machine. This color copier has a digital color image reader section at the top and a digital color image printer section at the bottom. In the reader unit, the original 30 is placed on an original platen glass 31 and is exposed and scanned by an exposure lamp 32 so that a reflected light image from the original 30 is condensed on a full color sensor 34 by a lens 33 and a color separation image signal is formed. obtain. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown), and is sent to a printer unit.

In the printer section, a photosensitive drum 1 serving as an image carrier is rotatably supported in the direction of an arrow. Around the photosensitive drum 1, a pre-exposure lamp 11, a corona charger 2, a laser exposure optical system 3, and a potential sensor 12 are provided. A transfer device 5 including four developing units 4y, 4c, 4m, and 4bk of different colors, an on-drum light amount detecting unit 13, 5a to 5i, and a cleaning unit 6 are arranged. In the laser exposure optical system 3, an image signal from a reader unit is converted into an optical signal by a laser output unit (not shown), and the converted laser light is converted into a polygon mirror 3a.
And is projected on the surface of the photosensitive drum 1 through the lens 3b and the mirror 3c.

When forming an image in the printer section, the photosensitive drum 1
Is rotated in the direction of the arrow to uniformly charge the photosensitive drum 1 after charging by the pre-exposure lamp 11 by the charger 2, and irradiate the light image E for each separation color to form a latent image. next,
By operating a predetermined developing device, the latent image on the photosensitive drum 1 is developed, and a toner image based on a resin is formed on the photosensitive drum 1. The developing devices are eccentric cams 24y, 24c, 24
The operations of m and 24bk make it possible to selectively approach the photosensitive drum 1 in accordance with each separation color.

Further, the toner image on the photosensitive drum 1 is
The image is transferred from a recording material cassette 7 to a recording material supplied to a position facing the photosensitive drum 1 via a transfer system and a transfer device 5. In the present embodiment, the transfer device 5 includes a transfer drum 5a, a transfer charger 5b, and an adsorption charger 5c for electrostatically adsorbing a recording material.
A recording material carrying sheet 5f made of a dielectric material is provided on a peripheral opening area of a transfer drum 5a which is rotatably driven and has an attraction roller 5g, an inner charger 5d, and an outer charger 5e opposed thereto. Are integrally extended in a cylindrical shape. The recording material supporting sheet 5f uses a dielectric sheet such as a polycarbonate film.

As the transfer drum 5a rotates, the toner image on the photosensitive drum 1 is transferred by a transfer charger 5b onto a recording material carried on a recording material carrying sheet 5f. In this manner, a desired number of color images are transferred to the recording material sucked and conveyed to the recording material carrying sheet 5f to form a full-color image. In the case of full-color image formation, when the transfer of the four color toner images is completed in this way, the recording material is transferred to the transfer drum 5.
The sheet is separated from the sheet by the action of the separation claw 8a, the separation pushing roller 8b, and the separation charger 5h, and is discharged to the tray 10 via the heat roller fixing device 9. On the other hand, the post-transfer photosensitive drum 1
After the residual toner on the surface is cleaned by the cleaning device 6, the image forming process is performed again.

When images are formed on both sides of a recording material,
Immediately after the sheet is discharged from the fixing device 9, the conveyance path switching guide 19 is driven, and once guided to the reversing path 21a via the conveying vertical path 20, the rear end of the sheet fed by the reversal of the reversing roller 21b is moved to the top. And is retracted in the direction opposite to the direction in which the sheet is fed, and stored in the intermediate tray 22. Thereafter, an image is formed on the other surface again by the above-described image forming step.

Further, in order to prevent scattering of powder on the recording material carrying sheet 5f of the transfer drum 5a and adhesion of oil on the recording material, the fur brush 14 is interposed between the fur brush 14 and the recording material carrying sheet 5f. The cleaning is performed by the action of a backup brush 15 facing the roller 14 and a backup brush 17 facing the roller 16 via the oil removing roller 16 and the recording material carrying sheet 5f. Such cleaning is performed before or after image formation, and at any time when a jam (paper jam) occurs. In this example, the gap between the recording material carrying sheet 5f and the photosensitive drum 1 is arbitrarily set by operating the eccentric cam 25 at a desired timing and operating the cam follower 5i integrated with the transfer drum 5a. It has a possible configuration. For example, during standby or when the power is off, the interval between the transfer drum 5a and the photosensitive drum 1 is increased.

FIG. 4 is a block diagram of the color image reading apparatus. Note that this color image reading apparatus corresponds to the configuration of the reader section in FIG. The internal configuration of the color image reading apparatus includes a platen cover 109 and a platen glass 11.
1. Document illumination lamp 105, reflector umbrella 106, first mirror stand 113, second mirror stand 103, imaging lens 10
8, a CCD 110, and an image processing device 112. The lamp 105 and the first mirror table 113 scan the document 104 on the document table glass 111 at twice the speed of the second mirror table 103.

A color image document 104 placed on a document table glass 111 is irradiated by a lamp 105, and the reflected light is guided to a mirror 107 in a mirror table 113. The original image reflected light guided to the mirror 107 is reflected by the mirror 10.
1, further guided to the mirror 102, the imaging lens 108
The document image is projected on the CCD 110 via the. CCD
110 converts the projected document image into an electric signal and sends it to the image processing device 112. Image data from the image processing device 112 is sent to a color electrophotographic image forming device.

FIG. 5 is a block diagram of the image processing device 112 of the color image reading device. Reference numeral 110 denotes a three-line CCD that separates reflected light from a document into electric signals by color separation. The A / D converter 202 converts an analog RGB signal from the CCD 110 into a digital signal. The shading correction unit 203 corrects the sensitivity of each pixel of the CCD 110 and corrects the inclination of the light amount of the light source. The R (red), G (green), and B (blue) signals in the figure are 8-bit digital image signals output from the A / D converter 202.

The CCD 110 used in the present embodiment
In FIG. 1, three CCD line sensors for R (red), G (green), and B (blue) are arranged at a predetermined fixed distance. For this reason, this digital image signal is a signal having a temporal shift caused by a spatial shift. This time shift is corrected in the three-line connection unit 204.

The input masking unit 205 includes a CCD 110
Is performed to correct the RGB spectral characteristics to the standard RGB space. The LOG conversion unit 206 is a look-up table configured by a RAM, and includes R (red),
The luminance signals of G (green) and B (blue) are C
(Cyan), M (magenta), and Y (yellow) are converted into density signals.

The masking / UCR unit 207 performs an operation for removing dust from the input C (cyan), M (magenta), and Y (yellow) density signals to the color of the toner used for print recording, and Bk ( Black) signal generation. The F value correction unit 208 is a correction table for correcting the density value (F value) for each color in accordance with the specification of the density to be printed. The color image signal 209 subjected to the series of image processing as described above is sent to a color electrophotographic image forming apparatus, and a color image is formed.

FIG. 6 is a circuit diagram of the motor control unit and the power variable unit. First, the motor control unit will be described. FIG.
, The rotation of the stepping motor 520 is controlled by MP
It is controlled by the motor drive circuit 527 by U524. Control information used for motor acceleration control, motor constant speed control, motor deceleration control, and back control is stored in ROM 52.
5 stored. The MPU 524 controls the stepping motor 520 according to the control information stored in the ROM 525.
Control.

Next, the power varying section will be described. The power variable unit includes a voltage switching circuit and a current switching circuit. In the voltage switching circuit, it is possible to switch between two types of voltages, a high voltage V-HIGH and a low voltage V-LOW. V-SW is a control signal for voltage switching. When the voltage of V-SW is “L”,
The transistors 532 and 515 are turned off, and the stepping motor 520 receives V
A voltage of -LOW is supplied. V-SW voltage is "H"
At this time, the transistors 532 and 515 are turned on, and the transistor 515 is connected to the stepping motor 520.
, A V-HIGH voltage is supplied. The V-SW control signal is output from the built-in output port PO5 of the MPU 524.

In the current switching circuit, the MPU 52
4, the current value flowing through the stepping motor 520 can be set arbitrarily. The OSC 507 outputs a triangular wave at a predetermined frequency. The value of the current flowing through the stepping motor 520 is converted into a voltage by the current detection resistor 518. The voltage corresponding to the motor current generated by the current detection resistor 518 has its noise component removed by a filter circuit including a resistor 510 and a capacitor 511, and is input to the non-inverting input terminal of the OP amplifier 505. A reference voltage corresponding to the amount of current flowing through the stepping motor 520 is input to the inverting input terminal of the OP amplifier 505.

The OP amplifier 505 compares a voltage corresponding to the motor current at the non-inverting input terminal with a reference voltage at the inverting input terminal and outputs a comparison voltage. The comparator 501 performs pulse width modulation using the comparison voltage and the triangular wave, and controls ON / OFF of the switching transistor 517.
Through the above series of operations, the value of the current flowing through the stepping motor 520 is controlled to a constant current corresponding to the reference voltage.

The switching of the current flowing through the stepping motor 520 is performed by varying the reference voltage applied to the inverting input terminal of the OP amplifier 505. The reference voltage is MP
The D / A converter 523 is set by U524. The D / A converter 523 has outputs of two channels, CH1 and CH2, and can set two reference voltages. One of the two reference voltages is selected by the multiplexer 530 and supplied to the inverting input terminal of the OP amplifier 505. The channel switching signal (SEL signal) of the multiplexer 530 is output from the built-in output port PO1 of the MPU 524.

FIG. 7 shows an MP for setting current / voltage values.
It is an operation | movement flowchart of U524. When starting acceleration / constant speed, deceleration / back operation, be sure to use the MPU 524 in FIG.
The operation shown in FIG. When the current / voltage value setting operation is started, it is determined whether to start the acceleration / constant speed operation (step S101).

When the acceleration / constant speed operation is started, the V-SW signal is set to "H" in order to set the voltage applied to the motor to the acceleration / constant speed voltage (step S102). The reference voltage at the time of acceleration / constant speed is set to CH1 of the D / A converter 523 (step S103). In addition, the reference voltage at the time of deceleration / back is set to D / A for the next deceleration / back operation.
Set to CH2 of converter 523 (step S10
4). The SEL signal is set to “L” to select Ach of the multiplexer 530 so that the reference voltage supplied to the motor constant current circuit is set to the acceleration / constant speed reference voltage (step S).
105). After that, the operation moves to step S106. If the acceleration / constant speed operation is not currently started in step S101, the operation proceeds to step S106.

In step S106, it is determined whether to start the deceleration / back-up operation. When starting the deceleration / back-up operation, the V-SW signal is set to “L” in order to set the voltage applied to the motor to the deceleration / back-up voltage (step S107). The SEL signal is set to "H" to select the Bch of the multiplexer 530 so that the reference voltage supplied to the motor constant current circuit is set to the reference voltage at the time of deceleration / back (step S108). Thereafter, the operation returns to the main operation. If the deceleration / back-up operation is not started at step S106, the operation returns to the back main operation.

By such an operation, a current and a voltage of the motor torque 1 used for the acceleration / constant speed operation for reading the image by the motor are supplied to the motor. Also, the motor is supplied with the current and voltage of the motor torque 2 used for the deceleration operation performed after the end of the image reading constant speed drive and the back operation for returning from the motor stop position to the scan start position.
As a result, a series of scan operation times can be shortened and SP
M can be improved.

Next, a second embodiment of the present invention will be described. The configurations of a color copying machine, a color image reading device, and an image processing device used in the present embodiment are the same as those shown in FIGS.

FIG. 8 is a circuit diagram of the motor control unit and the motor power variable unit. FIG. 8 is different from FIG. 6 in that an AND circuit 531 is connected to the MPU 524, and the other parts are the same as those in FIG. As will be described later, signals PULSE2 and TRG1 are added to the AND circuit 531 from the ports PO3 and PO4 of the MPU 524, and the output SC is sent to the port PI2 of the MPU 524.

In this embodiment, when the stepping motor is driven at a constant speed after the end of acceleration, the required load torque Tt2
(FIG. 2) only. For this purpose, the motor vibration during the constant speed drive period is reduced by reducing the power applied to the motor by a predetermined amount during the constant speed rotation in which the excitation state of the motor is sufficiently stable so as to eliminate unnecessary acceleration torque Tk2. We try to reduce it as much as possible.

FIG. 9 is a timing chart for switching the power flowing through the stepping motor 520. In FIG. 9, 5
00 represents the rotational acceleration of the motor. The x-axis indicates time, and the y-axis indicates acceleration. The range p indicates one step of the stepping motor operation. During the period of k, the acceleration control is performed. After the part e, the constant speed control is performed.
The portion c is a portion where the vibration due to the one-step operation of the stepping motor is sufficiently attenuated and the excitation is stable. In this part c, switching of current and voltage is performed.

PULSE1 is one of the stepping motors.
This is a reference pulse signal for performing a step operation, and the stepping motor rotates one step in one cycle of this PULSE1. PULSE2 is a pulse signal whose phase has been sent by １ ／ cycle of PULSE1. As the TRG1 signal, a pulse for one period of PULSE1 is output when the above-described acceleration control of the stepping motor ends and the constant speed control starts. This TRG1 signal is output from an output port PO4 built in the MPU 524. The SC signal is a motor power switching signal, which is obtained by ANDing the TRG1 signal and the PULSE2 by the AND circuit 531. When the TRG1 signal is "H", the PULSE2 signal is output. The SC signal is input to an input port PI2 built in the MPU 524.

REF-SW is a current switching signal,
The channel of the multiplexer 530 is switched according to the REF-SW signal. PWM indicates that pulse width modulation is performed using a comparison voltage and the triangular wave. OU
T is a PWM pulse for controlling ON / OFF of the switching transistor. CUR represents a current value flowing through the stepping motor. VOL represents a voltage value applied to the stepping motor.

As described above, in the portion e where the acceleration control is completed and the constant speed control is started, in the portion c where the vibration caused by the one-step operation of the stepping motor is sufficiently attenuated and the excitation is stabilized, A power switching signal SC is generated. Then, the switching of the current and the voltage is performed at the falling edge of the motor power switching signal SC. The above is the description of the motor power switching operation from the acceleration control to the constant speed control. Similarly, when switching from the constant speed control to the deceleration control, the current and voltage values according to the deceleration acceleration are returned, and the back operation is performed at high speed. Is performed.

FIG. 10 shows M for setting current / voltage values.
It is an operation | movement flowchart of PU524. Acceleration, constant speed, deceleration,
When the back operation is started, the operation shown in FIG. 10 is always performed in the MPU 524. When the current / voltage value setting operation is started, it is determined whether to start the acceleration operation (step S901).

To start the acceleration operation, the V-SW signal is set to "L" in order to set the voltage applied to the motor to the acceleration voltage (step S902). The reference voltage during acceleration is D
It is set to CH1 of / A (step S903). Also,
For the next constant speed operation, the reference voltage at the constant speed is set to D / A
(Step S904). The SEL signal is set to “L” so that the reference voltage supplied to the motor constant current circuit becomes the reference voltage for acceleration, and the multiplexer 530
Is selected (step S905). After that, the operation moves to step S906. Step S901
If the acceleration operation is not to be started at present, step S906
Move the operation to

In step S906, it is determined whether to start the constant speed operation. When the constant speed operation is started, the TRG1 signal is output for one period of PULSE1 at the start of the constant speed operation (step S907). Further, for the next deceleration operation, the reference voltage at the time of deceleration is set to D / A 1ch (step S908). Then, step S90
Move the operation to 9. If the acceleration operation is not currently started in step S906, the operation moves to step S909.

In step S909, it is determined whether to start a deceleration operation. When the deceleration operation is started, the V-SW signal is set to "L" in order to set the voltage applied to the motor to the deceleration voltage (step S910). The SEL signal is set to “L” so that the reference voltage supplied to the motor constant current circuit is set to the reference voltage at the time of deceleration.
Is selected (step S911). In addition, for the next back operation, the reference voltage at the time of back is set to D / A.
(Step S912). After that, the operation moves to step S913. If the deceleration operation is not currently started in step S909, the operation moves to step S913.

In step S913, it is determined whether to start the back operation. When the back operation is started, V- is applied to make the voltage applied to the motor the back voltage.
The SW signal is set to "L" (step S914). The SEL signal is set to “H” to select the Bch of the multiplexer 530 so that the reference voltage supplied to the motor constant current circuit becomes the reference voltage at the time of back (step S915).
Thereafter, the operation returns to the main operation. At step S913,
If the back operation is not started, the operation returns to the back main operation.

FIG. 11 is a flowchart of the interrupt operation of the MPU 524. MPU 524 interrupt terminal (INT
1) When the falling edge of the motor power switching signal SC is input to PI2, the interrupt operation shown in FIG. 11 is performed, and the current / voltage of the motor is switched. At the start of this interrupt operation, S is set so that the reference voltage supplied to the motor constant current circuit is changed from the acceleration current to the reference voltage at the time of constant speed current.
By setting the EL signal to “H”, the Bch
Is selected (step S1001). Next, the V-SW signal is set to “H” to make the voltage applied to the motor a constant speed voltage.
(Step S1002). When the above operation is completed, the operation returns to the main operation.

Next, a third embodiment of the present invention will be described. This embodiment is a case where the present invention is applied to a color copying machine that forms a color image using four photosensitive drums. 12 is a diagram showing a color image forming apparatus, FIG. 13 is a diagram showing its image processing unit, and FIG. 14 is a diagram showing a printer unit.

In FIG. 12, reference numeral 300 denotes a color scanner unit, 110 denotes a CCD, and 311 denotes a substrate on which the CCD 101 is mounted. Reference numeral 312 denotes an image processing unit.
A portion excluding the CD 110 and 211 and 212 to FIG.
215 parts. Reference numeral 301 denotes a document table glass (platen); 302, a document cover plate; 303 and 304, a light source (a halogen lamp or a fluorescent lamp) for illuminating the document;
And 306 are reflectors for condensing the light of the light sources 303 and 304 on the original, 307 to 309 are mirrors, 310 is a lens for condensing the reflected or projected light from the original on the CCD 101,
314 is the halogen lamps 303 and 304 and the reflector 30
Carriage for housing 5, 306 and mirror 307, 31
5 is a carriage that houses the mirrors 308 and 309, 31
A stepping motor 6 drives the carriage 314 and the carriage 315.

An image forming portion on a recording sheet will be described. 317 is an M image forming unit, 318 is a C image forming unit, 3
Reference numeral 19 denotes a Y image forming unit, and 320 denotes a K image forming unit. Since the respective components are the same, the M image forming unit 317 will be described in detail here, and the description of the other image forming units will be omitted. In the M image forming unit 317, reference numeral 342 denotes a photosensitive drum.
A latent image is formed on the surface by the light from the fourth LED array 210. A primary charger 321 charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for forming a latent image. A developing device 322 develops the latent image on the photosensitive drum 342 to form a toner image. The developing device 32
2 includes a sleeve 345 for developing by applying a developing bias. A transfer charger 323 discharges electricity from the back of the transfer belt 333,
The upper toner image is transferred to a recording sheet on the transfer belt 333 or the like. In this embodiment, since the transfer efficiency is high, the cleaner is not provided, but there is no problem even if the cleaner is mounted.

Next, the structure and procedure of a portion for forming an image on a recording paper or the like will be described. Cassette 340, 341
The recording paper stored in the pickup rollers 339 and 33
8, the paper is supplied onto the transfer belt 333 by the paper feed rollers 336 and 337 one by one. The fed recording paper is charged by the adsorption charger 346. Reference numeral 348 denotes a transfer belt roller which drives the transfer belt 333 and
6, the recording paper is charged, and the recording paper is attracted to the transfer belt 333. Reference numeral 347 denotes a paper edge sensor of a conventional reflection type photosensor, which detects the edge of the recording paper on the transfer belt 333. The detection signal of the paper leading edge sensor is sent from the printer unit to the color scanner unit 300, and is used as a sub-scan synchronization signal when a video signal is sent from the color scanner unit 300 to the printer unit.

The toner image is formed on the surface of the recording paper conveyed by the transfer belt 333 in the image forming units 317 to 320 in the order of MCYK. Delay amount T1, T
The images of the respective drums are accurately aligned by 2, T3 and T4. The recording paper that has passed through the K image forming unit 320 at the last stage is separated from the transfer belt 333 after the charge is removed by the charge removing charger 349 to facilitate separation from the transfer belt 333. Reference numeral 350 denotes a peeling charger, which prevents image disturbance due to peeling discharge when the recording paper separates from the transfer belt 333. The separated recording paper is charged by pre-fixing chargers 351 and 352 in order to compensate for toner attraction and prevent image disturbance, and then the fixing unit 334.
After the toner image is thermally fixed, the sheet is discharged to a sheet discharge tray 335.

Next, the image processing unit 312 will be described with reference to FIG. The document on the platen glass 301 in FIG. 12 reflects light from the light sources 303 and 304, and the reflected light is guided to the CCD 101 and converted into an electric signal. In addition,
When the CCD 101 is a color sensor, the RGB color filters may be inline on a one-line CCD in the order of RGB, or may be a three-line CCD in which an R filter, a G filter, and a B filter are arranged for each CCD. Alternatively, the filter may be on-chip or the filter may have a different structure from the CCD.

The electric signal (analog image signal) is sampled and held (S / H) by the clamp & Amp & S / H & A / D section 122, and the dark level of the analog image signal is clamped to the reference potential and amplified to a predetermined amount (see above). The processing order is not limited to the notation order), A / D converted, and converted into, for example, a digital signal of 8 bits for each of RGB. Then, the RGB signals are subjected to shading correction and black correction in a shading unit 123.

After that, when the CCD 110 is a three-line CCD in the splicing & MTF correction & original detecting unit 124, the splicing process differs in the reading position between the lines, so the delay amount for each line is adjusted according to the reading speed. The signal timing is corrected so that the line reading positions are the same. Also,
In the MTF correction, since the reading MTF changes depending on the reading speed and the magnification, the change is corrected, and the document detection recognizes the document size by scanning the document on the platen glass.

The digital signal whose reading position timing has been corrected is input to the CCD 110 by the input masking unit 125.
Spectral characteristics and light sources 303, 304 and reflector 305,
The spectral characteristic of 306 is corrected. Input masking section 125
Is a selector 1 that can be switched with an external I / F signal.
26. The signal output from the selector 126 is input to the color space compression & background removal & LOG conversion unit 127 and the background removal unit 135.

After the signal input to the background removal unit 135 is removed from the background, the signal is input to a black character determination unit 136 that determines whether or not the document is a black character in the document, and a black character signal is generated from the document. Also, the color space compression & background removal & LOG conversion unit 12 to which the output of the other selector 126 is input.
In step 7, it is determined whether or not the image signal read for color space compression is within the range that can be reproduced by the printer. to correct. Then, a background removal process is performed, and the RGB signals are converted into CMY signals by LOG conversion.

The timing of the output signal of the color space compression / background removal / LOG converter 127 is adjusted by the delay unit 128 in order to correct the signal and timing generated by the black character determination unit 136. The two types of signals are subjected to moiré removal by the moiré removal unit 129, and are subjected to scaling processing in the main scanning direction by the scaling unit 130. Next, in the UCR & masking & black character reflecting section 131, the CMY signal processed by the scaling section 130 is subjected to UCR processing to generate a CMYK signal, which is corrected by the masking processing into a signal which was present at the output of the printer, and the UCR & Masking & black character judgment part 1
The determination signal generated at 31 is fed back to the CMYK signal. UCR & Masking & Black Text Reflection Unit 131
Is subjected to density adjustment by the γ correction unit 132 and then subjected to smoothing or edge processing by the filter unit 133.

The signal processed as described above is converted from an 8-bit multi-level signal into a binary signal by the binary converter 211 in FIG. This conversion method may be any one of a dither method, an error diffusion method, and an improved error diffusion method.

Next, the printer section of FIG. 14 will be described. The LED image recording will be described. FIG. 12 and FIG.
The binary CMYK image signal generated by the third image processing unit 312 and obtained from the binary conversion unit 211
The difference between the distance between the leading edge position of the paper and the respective image forming units is adjusted by the delay units 216 to 219 via. This makes it possible to print four colors at predetermined positions. The LED driving units 220 to 223 generate signals for driving the LED units 224 to 227.

FIG. 15 shows the color scanner unit 300 of FIG.
5 shows a drive system for moving the carriage 314 by the motor 316. It is assumed that the carriage 314 in FIG. 12 is always controlled by a movement amount of a half of the carriage 315. 360 is a wire for transmitting the power of the motor 316 to the carriage 314. 3
Reference numeral 61 denotes a pulley for applying tension to the wire 360 to make it rigid. 362 and 363 are carriages 3
14 is a guide for stabilizing the reciprocating operation of the fourteenth embodiment.

By controlling the rotation / stop position of the motor 316 with the above configuration, the carriage 314 including a unit for taking in an image can be moved to an arbitrary position. In addition, while controlling to operate at a constant speed, by capturing an image from the CCD 110,
It is possible to take in the document two-dimensionally as image data.

Next, a method for controlling the stepping motor 316 will be described. FIG. 16 is an external view of the motor 316. The stepping motor 316 is a motor whose rotation amount can be controlled by a given pulse pattern. Reference numeral 401 denotes an A-phase input terminal, 402 denotes a B-phase input terminal, 403 denotes an Abar input terminal, and 404 denotes Bbar.
405 is a com input terminal for supplying power to the motor.

FIG. 17 shows an example of pulses required to drive this stepping motor. This pulse is referred to as a motor phase pattern. FIG. 18 shows the operating state of the motor. Here, the driving by the two-phase excitation method shown in the example of FIG. 17 will be described. In FIG. 17, reference numeral 410 denotes FIG.
8 State 0. 411 is the stat in FIG.
For e1, 412 is state2 and 413 is st
ate3.

During actual operation, these states 0 and 3
Must be repeated in the same direction. Each time the state is switched from a certain state to the next state, the motor shaft rotates by a fixed amount specific to the motor. In FIG. 17, state0 to state3 are repeated three times, and four state3 are repeated three times, so that 12 pulses of 3 × 4 are given to the motor. Therefore, the pulse can be moved 12 steps.

Further, since the rotation direction is determined by the transition direction of the state, if the moving method in which the state 0 to the state 3 are repeated in order is a normal rotation, the state 3 to the state 3
The moving method that moves in the order of e0 is reversed.

According to the above driving method, the rotation speed is determined by the interval at which the pulse is emitted. Here, pps (Palse par Sec.) Is used as the unit of the rotation speed of the motor. This indicates how many pulses the motor moves in one second. In other words, a state transition of 2000 times per second is called 2000 pps, and a pulse input of 4000 times is similarly 4000 pps. 4000pp
s indicates that the rotation axis is rotating at a speed twice as high as 2000 pps.

FIG. 19 shows that the stopped motor is 500 pp.
s, and accelerates to 4000 pps
This is a graph showing a case where the motor is rotated at a constant speed of pps and then decelerated to 500 pps and stopped. The y-axis indicates the rotation speed of the motor, and the x-axis indicates the total time that elapses from the point 0 when the motor starts driving.

In FIG. 19, 420 to 429 indicate the total time from point 0 where the first to tenth pulses are output and the speed at that time. Note that FIG.
In the description, the line between the circles indicating the timings of issuing the pulses 420 to 429 is connected by a line, but, of course, ideally, there is no intermediate value between these in terms of electric signals. Also,
In reality, 4000p with a small number of pulses as shown in FIG.
It is considered that there is no motor capable of accelerating to ps, but in the present embodiment, the number of pulses is set to 10 for simplification of description.

Pps = 1 / x (1) In Expression (1), x represents the time from the output of the previous pulse to the output of the next pulse. When x = 2 msec, 500 pps is obtained from the same expression. Becomes Also, 1000 pps when x = 1 msec and 2000 pps when x = 0.5 msec
It is 4000 pps when ps and x = 0.25 msec.

The pulse 420 indicates the first pulse from the start of operation of the motor (point 0), which is output 2 msec after the previous pulse output.
Is 1 msec, 422 is 0.5 msec, 423 to 42
Pulses are output at intervals of 0.25 msec until 6 and thereafter as shown in FIG. 17, and the rotation speed at that time is the speed shown on the y-axis.

Next, the operation of outputting a motor drive pulse by the CPU will be described. FIG. 20 is a hardware block diagram of a motor control system for performing the above description. A CPU 440 decodes a program stored in the memory 441 and controls the entire sequence. 441
Is a memory. In the present embodiment, a read-only memory (ROM) and a read / write memory RAM are integrated.

Reference numeral 442 denotes a DM capable of performing data transfer between the memory 441 and the I / O without the intervention of the CPU 440.
A has the role of transferring data from the memory 441 to the timer 443. Reference numeral 443 denotes a timer, and the motor 316
To determine the period for operating. 444 is a bus line. Reference numeral 445 denotes a motor driver, which is an MPLS in FIG.
Is an IC that detects a rising edge and automatically generates a pulse like A to Bbar by giving a pulse like this. 316, a motor; 447, a pulse counter; and 448, a power supply unit for applying power to the motor 316.

Next, each of the blocks shown in FIG. 20 will be described in more detail. The description of the CPU 440 and the memory 441 is omitted because it is a normal usage. FIG. 21 is a block diagram of the timer 443. 444 is a bus line in FIG. 20, 460 is a counter that counts up an internal register by an oscillator 461, 461 is an oscillator that supplies a clock source necessary for counting up the counter 460, and 462 and 463 are numerical comparisons with the counter 460. Is a comparison register for performing the following. 464 is counter 4
A comparator for comparing the output of the comparator 60 with the outputs of the comparison registers 462 and 463.
Change the state of.

FIG. 22 shows a timer output signal output from terminal 465. The Y axis indicates the value of the counter 460,
The X axis indicates the elapsed time. The sawtooth wave 602 is the value of the counter 460. The dotted line indicated by 601 is the count value indicated by the comparison register B463. Reference numeral 606 is a dotted line indicated by the counter of the comparison register A462.

The comparator 464 compares the output of the counter 460 with the output of the comparison register B 463, and switches the timer output of the terminal 465 to L when they become the same, that is, at the point 604 in FIG. Also, the output is compared with the output of the comparison register A 462, and when they are the same,
, The timer output is switched to H, and the count value of the counter 460 is set to 0. With this mechanism, a pulse can be output from the terminal 465.

The timer output of terminal 465 is input to DMA 442 and motor driver 445 via signal line 446 in FIG. The DMA 442 performs transfer at the rising edge of the signal on the signal line 446. This transfer is performed in memory 4
The time until the next pulse on 41, that is, the motor table, is transferred to the comparison register A462. This operation corresponds to 603 in FIG.

As described above, the operation (603) of adding a new value to the comparison register A 462 is performed at the timing of 605, and by changing the dotted line of 606, the time from the rising edge of the previous timer output to the next rising edge is reduced. Can be specified. By utilizing this, it is possible to arbitrarily control the switching timing of the stepping motor 316 given to the motor driver 445.

FIG. 23 shows the contents of data transmitted by the DMA 442 to the timer 443. 8M oscillator 461
When pps is calculated using Expression (1) when the frequency is Hz, the values of the memories 481 to 490 are 420 in FIG.
~ 429 pps. Reference numeral 491 denotes a transfer source index used by the DMA. After one transfer,
The setting for moving the index to the address indicated by the data to be transferred next is used.

The motor driver 445 shown in FIG.
5 is input through a signal line 446. The input is the MPLS in FIG. 17, and the rising edge of this pulse allows the signals A, Abar, B, and Bbar to be applied to the terminals 401 to 404 in FIG. 16 to be switched according to the state in FIG. L of each state
A current flows from the power supply unit 448 to the signal line of, and the motor rotates.

Therefore, the present system can drive the stepping motor 316 without considering the phase pattern given to the motor 316 by the CPU 440. In addition, the motor driver 445 switches the phase switching order, that is, switches the state related to the rotation direction of the motor to 0, 1, 2, 3 directions, or 3, 2, or 3.
There are a direction control line for selecting whether to switch to the 1 and 0 directions and a hold line for controlling whether to supply electric power to the motor, but these are common and will not be described.

FIG. 24 is a block diagram of the pulse counter 447. A counter 620 counts the rising edge of the signal line 446. 446 is the motor driver 4
45 is a signal line of a drive pulse (MPLS) of a motor connected to the DMA 45 or the DMA 442 or the like. 621 is a comparison register C, 622 is a comparison register D, 623 is a counter 62
This is a comparator that compares 0 with each output of the comparison register C621. 624 is a counter 620 and comparison registers C and D6.
21 and 622 are comparators for comparing respective outputs.

6 which is the output of the pulse counter 447
The output waveforms at 25 and 626 are shown in FIG. X axis is time,
The Y axis is the count value. Dotted line 642 indicates comparison register C
621, the dotted line 643 indicates the value of the comparison register D622,
The curve indicated by 640 is the value of the counter 620. Since this value counts the phase switching signal of the motor on the signal line 446, when the carriage 314 in FIG. 15 comes to an arbitrary position, an arbitrary output 625, 626 is output according to the set values of the comparison registers C, D621, 622. It is possible.

The comparator 623 compares the output of the counter 620 with each output of the comparison register C621, and when they match (64
In 4), the output of 625 is switched to H.
24 is a counter 620 and comparison registers C, D621, 6
22 are compared, the output of 626 is set to H when it matches with the comparison register D622 (645), and the output is set to L when it matches with the comparison register C (644).

FIG. 26 shows the motor driver 445 and the power supply unit 4.
It is a figure showing the power supply part which consists of 48. 660 is 40
Reference numeral 661 denotes a 24V power supply. Reference numeral 662 denotes a switch that opens and closes in response to a signal 625 output from the pulse counter 447. 663 and 664 are diodes for preventing current from flowing backward.

When the output of the above 625 is L, the switch 662 is opened, and 24 V which is the voltage of the power supply 661 appears at the terminal 405. When the output of 625 is H, 40 V which is the voltage of the power supply 660 appears at the terminal 405. At this time, since the power supply 661 is lower than the voltage of the terminal 405, the diode 664 is closed and not used. Thus, the voltage applied to the motor 316 can be controlled by the output waveform 625.

FIG. 27 shows the control method described above. The X-axis shows the elapsed time, and the Y-axis shows the operation / stop / rotation direction / rotation speed of the motor. Further, the line at y = 0 indicates a state where the motor is stopped. The further away from y = 0, the higher the speed in the forward direction. The farther the line away from y = 0, the higher the speed in the backward direction. Indicates that it is rotating.

That is, the motor operation shown in FIG. 27 is performed by accelerating in the forward direction to the speed 10 in only one time, moving in the forward speed 10 for the time obtained by adding 2 and 3, and performing the motion in the fourth time. , Stop the motion for 5 hours, accelerate in the backward direction to the speed 11 in the time 6, perform a constant speed motion for the time 7, and stop in the time 8. Since the movement of the motor 316 and the movement of the carriage 314 are linked, the carriage 314 reciprocates in the same manner as the operation of the motor.

The motor pulse count value in the figure is the count value of the pulse counter 447. The comparison register C,
An image reading signal and a motor power switching signal are output at 645 and 644 according to the values of D621 and 622. The motor drive voltage can be changed by the motor power switching signal.

If the motor power switching signal can be generated between the end of the image reading signal and the stop of the motor, the same effect as in the present system can be obtained. However, as in the present embodiment, It is most effective to switch when the image reading signal ends. But C
If PU 440 is aware of these actions, then C
The PU 440 may output a motor power switching signal at an arbitrary timing.

FIG. 28 shows a flow of the CPU 440 for operating the motor. In step S560, the setting of the dotted line 643 in FIG. 27 is performed. It is set at a place delayed from the acceleration time of the forward motor by 1 by the approach time of 2. The second running time is set so as not to output an image reading signal only while the speed fluctuation of the carriage 314 is stopped. In step S561, FIG.
7 is set to 644. In the present embodiment, the control for stopping the motor is performed immediately when the image reading area is completed. However, these controls need not always be the same. In step S562, the motor pulse count value is set to 0. In step S563, settings necessary for operating the motor in the forward direction are performed. In step S564, the motor is operated in the forward direction, and in step S565, the process waits for the motor to stop.

The motor operates at 24 V because the motor power switching signal is L, and the image reading signal becomes H at the point 645 in FIG. An image is read while performing a constant speed movement at a predetermined speed, and the image reading signal becomes L at a point 644. At the same time, the motor power switching signal is H
As described above, the voltage applied to the motor is 40
V. At this time, the motor table for stopping the motor can be controlled in a short time 4 because the motor can be controlled with a torque corresponding to 40 V.

The motor stops, and the process moves to step S566. In step S566, a weight is applied for 5 for a short time, and in step S567, setting for moving the motor in the backward direction is performed. Since the motor power switching signal remains at H, the motor operates in the backward direction at step S568 with the voltage kept at 40 V, and waits for the motor to stop at step S569. When the motor stops, the process moves to step S570, sets the motor power switching signal to L, and ends.

By controlling as described above, the carriage 31 is driven at a low voltage when reading an image.
4 is controlled so as to be as small as possible, and by switching to a high voltage when the image reading range is exceeded, the control is performed in the stop / return direction at high speed, whereby the reciprocating operation can be performed as quickly as possible. .

Next, a fourth embodiment will be described. The present embodiment is characterized in that the current is switched using the motor power switching signal generated in the third embodiment. The configurations, operations, control methods, and the like of the image forming apparatus, the image processing unit, the printer unit, and the like according to the present embodiment are the same as those described in the third embodiment, and thus description thereof will be omitted.

FIG. 29 shows a diagram of the current switching unit used in the present embodiment. The motor 316 is a motor similar to that of the third embodiment. The voltage of the power supply unit 448 is fixed at 40 V. The motor driver 445 according to the third embodiment is provided with a current limiter terminal 683, and the current flowing through the motor 316 can be limited by a resistor connected thereto.

In the third embodiment, the power is switched by changing the voltage. In this embodiment, the switch 682 is switched by the motor power switching signal 625.
And the power of the motor is switched by selecting either the resistor 680 or the resistor 681. Thereby, the same effect as that of the third embodiment can be obtained. In addition, power can be controlled by one power supply.

Next, a fifth embodiment will be described. This embodiment provides a composite system according to the third and fourth embodiments. That is, the current and the voltage are simultaneously switched by the motor power switching signal 625 using the method of FIG. 26 and the method of FIG.

In each of the embodiments described above, the present invention has been described with respect to the case where the carriage in the image reading apparatus is reciprocated. However, the present invention is not limited to this, and the present invention is applicable to the case where another moving object is reciprocated by a motor. Can be applied.

[0103]

As described above, according to the present invention, the moving object can be returned to the original position at a high speed by making the electric power of the motor the same at the time of deceleration and at the time of reverse rotation. In the case of a device, the SPM can be improved.

Further, according to the present invention, the motor vibration can be suppressed by reducing the electric power of the motor after the transition from the acceleration to the constant speed.
Image blur and color shift can be eliminated.

Further, after the shift from the constant speed to the deceleration, by increasing the electric power, when performing the reverse rotation control, it is possible to eliminate the step-out of the motor and to return the moving object to the high speed.
In the case of an image reading device, the SPM can be improved.

[Brief description of the drawings]

FIG. 1 is a sequence chart of an image reading operation for explaining first and second embodiments of the present invention.

FIG. 2 is a characteristic diagram illustrating a relationship between a motor acceleration torque and a constant speed torque (load torque).

FIG. 3 is a configuration diagram of a color copying machine to which the first and second embodiments are applied;

FIG. 4 is a configuration diagram of an image reading apparatus to which the first and second embodiments are applied.

FIG. 5 is a block diagram of an image processing apparatus to which the first and second embodiments are applied;

FIG. 6 is a circuit diagram of a motor control unit and a power variable unit according to the first embodiment.

FIG. 7 is a flowchart of a control operation according to the first embodiment.

FIG. 8 is a circuit diagram of a motor control unit and a power variable unit according to a second embodiment.

FIG. 9 is a timing chart showing the operation of the second embodiment.

FIG. 10 is a flowchart of a control operation according to the second embodiment.

FIG. 11 is a flowchart of an interrupt operation of a computer according to the second embodiment.

FIG. 12 is a configuration diagram of an image forming apparatus to which the third, fourth, and fifth embodiments are applied.

FIG. 13 is a block diagram of an image processing unit.

FIG. 14 is a block diagram of a printer unit.

FIG. 15 is a configuration diagram of a color scanner unit.

FIG. 16 is an external view of a motor.

FIG. 17 is a timing chart showing driving pulses of a motor.

FIG. 18 is a characteristic diagram illustrating an operation state of a motor.

FIG. 19 is a characteristic diagram showing an operation of the motor.

FIG. 20 is a block diagram of a motor control system.

FIG. 21 is a block diagram of a timer.

FIG. 22 is a characteristic diagram showing a timer output.

FIG. 23 is a configuration diagram of a motor table.

FIG. 24 is a block diagram of a pulse counter.

FIG. 25 is a characteristic diagram showing an output of a pulse counter.

FIG. 26 is a configuration diagram of a power supply unit according to the third embodiment.

FIG. 27 is a characteristic diagram showing a motor control method.

FIG. 28 is a flowchart of a motor control operation.

FIG. 29 is a configuration diagram of a current switching unit according to a fourth embodiment.

[Explanation of symbols]

 30 original image a acceleration section b vibration absorption period c constant speed period (image reading period) d deceleration period e back period g scan start position 110 CCD 520 stepping motor 532, 515, 517 switching transistor 527 motor drive circuit 524 MPU 531 AND circuit 314 Carriage 316 Stepping motor 440 CPU 445 Motor driver 448 Power supply section

Claims (10)

[Claims] 1. A method for controlling the acceleration, constant speed, deceleration, and reverse rotation of the motor by transmitting the rotation of the motor to the moving object via a driving mechanism to reciprocate the moving object along a predetermined path. The method of controlling a motor, wherein the amount of power supplied to the motor is controlled to be the same during the deceleration control and the reverse rotation control. 2. By transmitting rotation of a motor to a moving object via a driving mechanism, in order to move the moving object along a predetermined path, control of acceleration, constant speed, and deceleration of the motor is sequentially performed. A method of controlling a motor to be performed, wherein the power supplied to the motor is reduced at a predetermined timing after shifting from the acceleration to the constant speed. 3. The motor according to claim 2, wherein the motor performs reverse rotation control to reciprocate the moving object, and increases the reduced power when the motor shifts from the constant speed to the deceleration. Motor control method. 4. The motor control method according to claim 1, wherein the control of the electric power is performed by controlling a voltage and / or a current supplied to the motor. 5. Control of acceleration, constant speed, deceleration and reverse rotation of the motor in order to reciprocate the moving object along a predetermined path by transmitting the rotation of the motor to the moving object via a driving mechanism. Control means for performing the above-mentioned respective controls and controlling the amount of electric power supplied to the motor to be the same during the deceleration control and the reverse rotation control. Characteristic motor control device. 6. By transmitting rotation of a motor to a moving object via a driving mechanism, each control of acceleration, constant speed, and deceleration of the motor is sequentially performed in order to move the moving object along a predetermined path. A motor control device for controlling the motor, the control device comprising: a control unit configured to perform the above-described respective controls, and to reduce electric power supplied to the motor at a predetermined timing after shifting from the acceleration to the constant speed. apparatus. 7. The control means performs reverse rotation control of the motor to reciprocate the moving object, and increases the reduced power when the speed is shifted from the constant speed to a deceleration. The motor control device according to claim 6. 8. The control of the electric power by the control means,
7. The motor control device according to claim 5, wherein the control is performed by controlling a voltage and / or a current supplied to the motor. 9. The motor control device according to claim 5, wherein the moving object is image reading means for optically reading a document image during the constant speed control. 10. The method according to claim 1, wherein the motor is a stepping motor, and the predetermined timing is a period in which the vibration after one step rotation of the stepping motor after the transition from the acceleration to the constant speed is sufficiently attenuated and the excitation is stable. 7. The motor control device according to claim 6, wherein: